Heretofore, in a measuring system where it is required to measure a plurality of different types of physical quantities or a plurality of the same type of physical quantities different in detection range, a plurality of separately-packaged sensors have been used. In this case, the plurality of separately-packaged sensors have to be mounted on a circuit board individually. This involves the need for assuring a large space (area) for mounting these physical-quantity sensors in the circuit board, which leads to undesirable increases in size, complexity and cost of the measuring system.
As one measure against this problem, it is conceivable to incorporate a plurality of sensors into a single package. For example, the following Patent Publication 1 discloses a compound sensor unit having a pressure sensor for detecting a pressure and a temperature sensor for detecting a temperature which are incorporated into a single package.
Patent Publication 1: Japanese Patent No. 3149957 (FIG. 2)